[libvirt] [PATCH] qemu:Add support L2 table cache for qcow2 disk
John Ferlan
jferlan at redhat.com
Wed Jun 27 10:44:06 UTC 2018
On 06/27/2018 03:50 AM, Allen Do wrote:
> The patch add support L2 table cache for qcow2 disk. L2 table cache can
> improve IO read and write performance for qcow2 img.
> Diff follows:
> src/conf/domain_conf.c | 47
> +++++++++++++++++++++++++++++++++++++++++++++++
> src/conf/domain_conf.h | 5 +++++
> src/qemu/qemu_command.c | 7 +++++++
> src/qemu/qemu_domain.c | 6 ++++++
> tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.args | 2 +-
> tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml | 3 ++-
> 6 files changed, 68 insertions(+), 2 deletions(-)
>
Before you go through too much trouble though, this has been attempted
before many times and each time it's been rejected for reasons described
in responses to those patches.
See:
https://www.redhat.com/archives/libvir-list/2017-November/msg00536.html
and
https://www.redhat.com/archives/libvir-list/2017-September/msg00553.html
John
>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index beca0be..0a6afca 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -8058,6 +8058,8 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
> char *domain_name = NULL;
> int expected_secret_usage = -1;
> int auth_secret_usage = -1;
> + char *disk_l2_cache_size = NULL;
> + char *disk_cache_clean_interval = NULL;
>
> if (!(def = virDomainDiskDefNew(xmlopt)))
> return NULL;
> @@ -8233,6 +8235,27 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr
> xmlopt,
> }
> } else if (xmlStrEqual(cur->name, BAD_CAST "boot")) {
> /* boot is parsed as part of virDomainDeviceInfoParseXML */
> + } else if (xmlStrEqual(cur->name, BAD_CAST "diskCache")) {
> + disk_l2_cache_size =
> + virXMLPropString(cur, "disk_l2_cache_size");
> + if (disk_l2_cache_size &&
> + virStrToLong_ui(disk_l2_cache_size, NULL, 0,
> + &def->disk_cache.disk_l2_cache_size) < 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("invalid disk L2 cache size '%s'"),
> + disk_l2_cache_size);
> + goto error;
> + }
> + disk_cache_clean_interval =
> + virXMLPropString(cur, "disk_cache_clean_interval");
> + if (disk_cache_clean_interval &&
> + virStrToLong_ui(disk_cache_clean_interval, NULL, 0,
> +
> &def->disk_cache.disk_cache_clean_interval) < 0) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("invalid disk cache clean interval '%s'"),
> + disk_cache_clean_interval);
> + goto error;
> + }
> }
> }
>
> @@ -8472,6 +8495,8 @@ virDomainDiskDefParseXML(virDomainXMLOptionPtr xmlopt,
> VIR_FREE(vendor);
> VIR_FREE(product);
> VIR_FREE(domain_name);
> + VIR_FREE(disk_l2_cache_size);
> + VIR_FREE(disk_cache_clean_interval);
>
> ctxt->node = save_ctxt;
> return def;
> @@ -20646,6 +20671,27 @@ virDomainDiskBlockIoDefFormat(virBufferPtr buf,
> }
> }
>
> +static void
> +virDomainDiskCacheDefFormat(virBufferPtr buf,
> + virDomainDiskDefPtr def)
> +{
> + if (def->disk_cache.disk_l2_cache_size > 0 ||
> + def->disk_cache.disk_cache_clean_interval > 0) {
> + virBufferAddLit(buf, "<diskCache");
> + if (def->disk_cache.disk_l2_cache_size > 0) {
> + virBufferAsprintf(buf,
> + " disk_l2_cache_size='%u'",
> + def->disk_cache.disk_l2_cache_size);
> + }
> + if (def->disk_cache.disk_cache_clean_interval > 0) {
> + virBufferAsprintf(buf,
> + " disk_cache_clean_interval='%u'",
> + def->disk_cache.disk_cache_clean_interval);
> + }
> + virBufferAddLit(buf, "/>\n");
> + }
> +}
> +
>
> /* virDomainSourceDefFormatSeclabel:
> *
> @@ -20990,6 +21036,7 @@ virDomainDiskDefFormat(virBufferPtr buf,
>
> virDomainDiskGeometryDefFormat(buf, def);
> virDomainDiskBlockIoDefFormat(buf, def);
> + virDomainDiskCacheDefFormat(buf, def);
>
> /* For now, mirroring is currently output-only: we only output it
> * for live domains, therefore we ignore it on input except for
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 91a33cb..83ea9d3 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -647,6 +647,11 @@ struct _virDomainDiskDef {
> unsigned int physical_block_size;
> } blockio;
>
> + struct {
> + unsigned int disk_l2_cache_size;
> + unsigned int disk_cache_clean_interval;
> + } disk_cache;
> +
> virDomainBlockIoTuneInfo blkdeviotune;
>
> char *serial;
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index e087891..7c47cd3 100755
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -1662,6 +1662,13 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk,
> if (qemuBuildDriveSourceStr(disk, cfg, &opt, qemuCaps) < 0)
> goto error;
>
> + if (disk->disk_cache.disk_l2_cache_size > 0)
> + virBufferAsprintf(&opt, "l2-cache-size=%u,",
> + disk->disk_cache.disk_l2_cache_size);
> + if (disk->disk_cache.disk_cache_clean_interval > 0)
> + virBufferAsprintf(&opt, "cache-clean-interval=%u,",
> + disk->disk_cache.disk_cache_clean_interval);
> +
> if (emitDeviceSyntax)
> virBufferAddLit(&opt, "if=none");
> else
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 9f165c1..de334a7 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -5408,6 +5408,12 @@ qemuDomainDiskChangeSupported(virDomainDiskDefPtr
> disk,
> CHECK_EQ(ioeventfd, "ioeventfd", true);
> CHECK_EQ(event_idx, "event_idx", true);
> CHECK_EQ(copy_on_read, "copy_on_read", true);
> +
> + CHECK_EQ(disk_cache.disk_l2_cache_size,
> + "diskCache disk_l2_cache_size", true);
> + CHECK_EQ(disk_cache.disk_cache_clean_interval,
> + "diskCache disk_cache_clean_interval", true);
> +
> /* "snapshot" is a libvirt internal field and thus can be changed */
> /* startupPolicy is allowed to be updated. Therefore not checked
> here. */
> CHECK_EQ(transient, "transient", true);
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.args
> b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.args
> index b405242..b968302 100644
> --- a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.args
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.args
> @@ -22,7 +22,7 @@ QEMU_AUDIO_DRV=none \
> -drive file=/dev/HostVG/QEMUGuest2,format=raw,if=none,media=cdrom,\
> id=drive-ide0-1-0,readonly=on \
> -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 \
> --drive file=/tmp/data.img,format=raw,if=none,id=drive-virtio-disk0 \
> +-drive
> file=/tmp/data.img,format=qcow2,l2-cache-size=536870912,cache-clean-interval=900,if=none,id=drive-virtio-disk0
> \
> -device virtio-blk-pci,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,\
> id=virtio-disk0 \
> -drive file=/tmp/logs.img,format=raw,if=none,id=drive-virtio-disk1 \
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
> b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
> index b843878..43298fb 100644
> --- a/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-virtio.xml
> @@ -28,8 +28,9 @@
> <address type='drive' controller='0' bus='1' target='0' unit='0'/>
> </disk>
> <disk type='file' device='disk'>
> - <driver name='qemu' type='raw'/>
> + <driver name='qemu' type='qcow2'/>
> <source file='/tmp/data.img'/>
> + <diskCache disk_l2_cache_size='53687'
> disk_cache_clean_interval='900' />
> <target dev='vda' bus='virtio'/>
> </disk>
> <disk type='file' device='disk'>
>
>
> Thanks
>
>
> --
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>
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